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Silastic
Silastic (a portmanteau of 'silicone' and 'plastic') is a trademark registered in 1948 by Dow Corning Corporation for flexible, inert silicone elastomer. Composition The Silastic trademark refers to silicone elastomers, silicone tubing and some cross-linked polydimethylsiloxane Polydimethylsiloxane (PDMS), also known as dimethylpolysiloxane or dimethicone, belongs to a group of polymeric organosilicon compounds that are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, as its ... materials manufactured by Dow Corning,United States Patent and Trademark Office, . Filing date June 15, 1946; registration date April 13, 1948. Owner: Dow Corning Corporation, Midland, Michigan 48686-0994. the owner of the global trademark. Applications Silastic-brand silicone elastomers have a range of applications. In the automotive industry they are used for making gaskets, spark plug boots, hoses and other components that must operate over a broad tempe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasolacrimal Duct Obstruction
Nasolacrimal duct obstruction is the obstruction of the nasolacrimal duct and may be either congenital or acquired. Obstruction of the nasolacrimal duct leads to the excess overflow of tears called epiphora. Sign and symptoms Excessive tearing is the most common complaint of patients with nasolacrimal duct obstruction, followed by acute or chronic infections. Pain at the side of the nose suggests dacryocystitis. Nasolacrimal duct obstruction is more common with increasing age and more common in females than males. Cause Involutional stenosis Involutional stenosis is probably the most common cause of nasolacrimal duct obstruction in older people. It affects women twice as frequently as men. Although the inciting event in this process is unknown, clinicopathologic study suggests that compression of the lumen of the nasolacrimal duct is caused by inflammatory infiltrates and edema. This may be the result of an unidentified infection or possibly an autoimmune disease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abdominal Wall Defect
Abdominal wall defects are a type of congenital defect that allows the stomach, the intestines, or other organs to protrude through an unusual opening that forms on the abdomen. During the development of the fetus, many unexpected changes occur inside the womb. Specifically, the stomach, intestines, or other organs begin to develop outside the fetus' abdomen through the abnormal hole in the abdomen and, as development progresses, the abdominal wall eventually encloses these organs. In some cases of defect either the umbilical opening is too oversized or has developed improperly which allows the organs to remain outside or to squeeze through the abdominal wall. There are two main types of abdominal wall defects that result due to the changes during development. They are omphalocele and gastroschisis. Gastroschisis develops when the abdominal wall does not completely close, and the organs are present outside of the infant's body. Omphalocele occurs when some of the organs protrude t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portmanteau
A portmanteau word, or portmanteau (, ) is a blend of wordsGarner's Modern American Usage , p. 644. in which parts of multiple words are combined into a new word, as in ''smog'', coined by blending ''smoke'' and ''fog'', or ''motel'', from ''motor'' and ''hotel''. In , a portmanteau is a single morph that is analyzed as representing two (or more) underlying morphemes. When portmanteaus shorten established [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicone
A silicone or polysiloxane is a polymer made up of siloxane (−R2Si−O−SiR2−, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cooking utensils, thermal insulation, and electrical insulation. Some common forms include silicone oil, silicone grease, silicone rubber, silicone resin, and silicone caulk. Chemistry More precisely called polymerized siloxanes or polysiloxanes, silicones consist of an inorganic silicon–oxygen backbone chain (⋯−Si−O−Si−O−Si−O−⋯) with two organic groups attached to each silicon center. Commonly, the organic groups are methyl. The materials can be cyclic or polymeric. By varying the −Si−O− chain lengths, side groups, and crosslinking, silicones can be synthesized with a wide variety of properties and compositions. They can vary in consistency from liquid to gel to rubber to hard plastic. The most common si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives. 9.2 billion tonnes of plastic are estimated to have been made between 1950 and 2017. More than half this plastic has been produced since 2004. In 2020, 400 million tonnes of plastic were produced. If global trends on plastic demand continue, it is estimated that by 2050 annual global plastic production will reach over 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dow Corning
Dow Corning Corporation, was an American multinational corporation headquartered in Midland, Michigan, United States. Originally established as a joint venture between The Dow Chemical Company and Corning Incorporated, Dow bought out Corning and Dow Corning became a 100% Dow subsidiary. After a brief existence as a DowDuPont-owned company, as Dow spun out from DowDuPont on April 1, 2019, it is now a new company, Dow Silicones Corporation, which is wholly owned by Dow and specializes in silicone and silicon-based technology, and is the largest silicone product producer in the world. History Dow Corning was formally established in 1943 as a joint venture between the American conglomerates Dow Chemical and Corning Glass to explore the potential of silicone and was a manufacturer of products for use by the U.S. military in World War II. The company began operating its first plant, in Midland, MI, in 1945. Dr. E. C. Sullivan was named president, and Dr. William R. Collings was nam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemically Inert
In chemistry, the term chemically inert is used to describe a substance that is not chemically reactive. From a thermodynamic perspective, a substance is inert, or nonlabile, if it is thermodynamically unstable (positive standard Gibbs free energy of formation) yet decomposes at a slow, or negligible rate. Most of the noble gases, which appear in the last column of the periodic table, are classified as inert (or unreactive). These elements are stable in their naturally occurring form (gaseous form) and they are called inert gases. Noble gas The noble gases ( helium, neon, argon, krypton, xenon and radon) were previously known as 'inert gases' because of their perceived lack of participation in any chemical reactions. The reason for this is that their outermost electron shells (valence shells) are completely filled, so that they have little tendency to gain or lose electrons. They are said to acquire a noble gas configuration, or a full electron configuration. It is now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastomer
An elastomer is a polymer with viscoelasticity (i.e. both viscosity and Elasticity (physics), elasticity) and with weak intermolecular forces, generally low Young's modulus and high Deformation (mechanics), failure strain compared with other materials. The term, a portmanteau of ''elastic polymer'', is often used interchangeably with Synthetic rubber, rubber, although the latter is preferred when referring to vulcanization, vulcanisates. Each of the monomers which link to form the polymer is usually a compound of several chemical elements, elements among carbon, hydrogen, oxygen and silicon. Elastomers are amorphous polymer A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...s maintained above their glass transition temperature, so that considerable segmental motion, molecular reconfo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polydimethylsiloxane
Polydimethylsiloxane (PDMS), also known as dimethylpolysiloxane or dimethicone, belongs to a group of polymeric organosilicon compounds that are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, as its versatility and properties lead to many applications. It is particularly known for its unusual rheological (or flow) properties. PDMS is optically clear and, in general, inert, non-toxic, and non-flammable. It is one of several types of silicone oil (polymerized siloxane). Its applications range from contact lenses and medical devices to elastomers; it is also present in shampoos (as it makes hair shiny and slippery), food (antifoaming agent), caulk, lubricants and heat-resistant tiles. Structure The chemical formula of PDMS is , where ''n'' is the number of repeating monomer units.Mark, J. E.; Allcock, H. R.; West, R. “Inorganic Polymers” Prentice Hall, Englewood, NJ: 1992. . Industrial synthesis can begin from dimethyldi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SUNY Downstate Medical Center
SUNY Downstate Health Sciences University (Downstate) is a public medical school and hospital in Brooklyn, New York. It is the southernmost member of the State University of New York (SUNY) system and the only academic medical center for health education, research, and patient care serving Brooklyn's 2.5 million residents. As of Fall 2018, it had a total student body of 1,846 and approximately 8,000 faculty and staff. Downstate Medical Center comprises a College of Medicine, Colleges of Nursing and Health Related Professions, Schools of Graduate Studies and Public Health, and University Hospital of Brooklyn. It also includes a major research complex and biotechnology facilities. SUNY Downstate ranks eighth nationally in the number of alumni who are on the faculty of American medical schools. More physicians practicing in New York City graduated from Downstate than from any other medical school. With 1,040 residents (young physicians in training), Downstate's residency prog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicones
A silicone or polysiloxane is a polymer made up of siloxane (−R2Si−O−SiR2−, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cooking utensils, thermal insulation, and electrical insulation. Some common forms include silicone oil, silicone grease, silicone rubber, silicone resin, and silicone caulk. Chemistry More precisely called polymerized siloxanes or polysiloxanes, silicones consist of an inorganic silicon–oxygen backbone chain (⋯−Si−O−Si−O−Si−O−⋯) with two organic groups attached to each silicon center. Commonly, the organic groups are methyl. The materials can be cyclic or polymeric. By varying the −Si−O− chain lengths, side groups, and crosslinking, silicones can be synthesized with a wide variety of properties and compositions. They can vary in consistency from liquid to gel to rubber to hard plastic. The most common siloxa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastomers
An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus and high failure strain compared with other materials. The term, a portmanteau of ''elastic polymer'', is often used interchangeably with rubber, although the latter is preferred when referring to vulcanisates. Each of the monomers which link to form the polymer is usually a compound of several elements among carbon, hydrogen, oxygen and silicon. Elastomers are amorphous polymers maintained above their glass transition temperature, so that considerable molecular reconformation is feasible without breaking of covalent bonds. At ambient temperatures, such rubbers are thus relatively compliant ( E ≈ 3 M Pa) and deformable. Their primary uses are for seals, adhesives and molded flexible parts. Application areas for different types of rubber are manifold and cover segments as diverse as tires, soles for shoes, and damping an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
